Filter assemblies comprising pleated media packs disposed in a frame structure are known. A pleated filter pack is typically formed from a sheet of filter media, e.g. a fiberglass sheet, or a nonwoven polyester sheet, which is pleated to increase the effective filtering area of the filter body. To provide mechanical support and/or to combine a plurality of media packs, the media pack is typically arranged in a frame structure. To prevent air from bypassing the filtering area of the media pack as it flows through the filter assembly, the edges of the media pack need to be sealed against the frame structure.
Herein, edges of the filter media pack having accordion like folds are generally referred to as open ends of the filter media pack. Edges of the filter media pack at the first and last pleat are referred to as closed ends. A known method to seal open ends when arranging media packs in the frame structure of the filter media pack is shown in US 2007/0204578 A1, which discloses a filter assembly comprising a pleated filter media pack which is arranged in a frame structure. The frame structure comprises a top panel and a bottom panel at which open ends of the pleated filter media pack are adhered and sealed by means of an adhesive, like a hot melt or other filter securing adhesive applied to the top and bottom panels of the frame assembly. After the adhesive is applied to the top panel and to the bottom panel of the frame structure, the open ends of the pleated media pack are subsequently put in contact with the adhesive as the filter assembly is mounted. The adhesive is then allowed to cure. This manner of sealing the media pack to the housing generally may provide a reliable seal, but requires a substantial amount of raw material, i.e. adhesive, and is time consuming to perform.